<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>曲线阴影</title>
    <style>
        div{
            width:500px;
            height:200px;
            line-height: 200px;
            margin:100px auto;
            background:#fff;
            text-align:center;
            box-shadow:0 0 30px rgba(0,0,0,.2) inset,0 0 5px rgba(0,0,0,.1);
            position:relative;
        }
        div::before,div::after{
            content:'';
            display:block;
            width:440px;
            height:100px;
            position:absolute;
            left:30px;
            bottom:0;
            background:#fff;
            border-radius:100px/20px;
            box-shadow:0 0 20px  rgba(0,0,0,.8);
            z-index:-1;
        }
    </style>
</head>
<body>
    <div>曲线阴影</div>
</body>
</html>
